Correcting a common, costly misconception about penicillin allergies
Edgar Mora, MD, Hospital Medicine, is Platte Valley’s physician champion fora new enterprise-wise initiative, Penicillin Allergy Delabeling using the PEN-FAST Calculator, recently approved as a standardized best practice to safely remove incorrect allergy labels from patient charts.
“We all know a great number of patients are mislabeled as being PCN allergic, but I really did not have an idea of the enormous percentage that they really are,” said Mora. “This effort to de-label patients is so simple and straightforward, that I am surprised it had not been done before.”
In fact, more than 90% of reported penicillin allergies are not true allergies. Penicillin delabeling is a high-value, low-risk intervention that improves care quality and reduces harm to patients and organizational and patient costs.
How does the delabeling process work using the PEN-FAST Calculation?
Risk assessment: A healthcare professional reviews the history of the reaction to determine risk.
PEN-FAST score of < 3 points equals low‑risk: Low probability of a positive penicillin oral challenge test (<5% risk)
Direct oral challenge: For low-risk patients, a single dose of amoxicillin is administered in a hospital setting to verify tolerance.
Removal: If the patient tolerates the oral challenge, the allergy label is removed from the medical record, and the patient is notified.
“This initiative will help us minimize cost for patients and for the system, and will enable us to avoid overutilizing broader antibiotics,” Mora said. “So, I’m happy to be part of it.”
Epic workflow support
Epic supports the penicillin allergy delabeling process through standardized pharmacist workflows. Pharmacists document the PEN‑FAST score in the Pharmacy Minimum Data flowsheet, which can then be pulled directly into the allergy comments using the smart phrase .rxpenfast.
Patients who meet low‑risk criteria based on the PEN‑FAST score are eligible for evaluation using the Intermountain Penicillin Allergy Challenge order set, supporting safe delabeling when clinically appropriate.
Patient education resources
Penicillin allergy fact sheets:
Patient safety and outcomes
Alternative antibiotics carry:
2–3 times higher risk of C. difficile
Higher rates of acute kidney injury and drug toxicity
Less effective treatment for common infections
Delabeling enables narrower, first‑line, guideline‑recommended therapy with better efficacy and fewer side effects
Unconfirmed allergy labels lead to the use of broader-spectrum antibiotics, which can cause increased side effects, antibiotic resistance, and poorer health outcomes
Cost and impact
$1,500–$4,000 savings per inpatient by avoiding higher cost alternative antibiotics, reducing length of stay, and reducing antibiotic-related and infection-related complications
One‑time delabeling provides lifelong benefit across future encounters
What this means for daily practice
Simpler antibiotic choices for hospitalists, nurses, and pharmacists
More accurate allergy lists and safer medication administration
Strong alignment with antimicrobial stewardship, quality, and value‑based care goals
Additional resources
More information is available on the Antimicrobial Stewardship website.
Questions? Contact Mora, Whitney Buckel, PharmD, or Robert Silge, MD.